1. Field of the Invention
The present invention relates to a projector, and more specifically, to a projector containing optical components with adjustable positions for adjusting an offset of projected images.
2. Description of the Prior Art
Image projectors, including digital projectors, are becoming increasingly popular for giving presentations or for home or office use. When setting up a projector for a specific location, the projector must be placed a suitable distance from a screen or other viewing surface. In addition, the projector must be positioned at a proper height and projection angle with respect to the horizontal. Since adjusting the projecting angle is such a common task, many projectors are equipped with adjustable legs positioned under one or more edges of the projector for raising or lowering the projector. By manually changing the height of the adjustable legs, images projected by the projector can be displayed on the proper area of the screen. However, the greater the angle in which the projector is raised, the more distorted the projected image will be. Distortion causes the projected images to appear as a trapezoid. In addition, the projected light intensity is not uniform for the entire image projected on the screen.
Unfortunately, changing the height of the adjustable legs may involve interruption of the presentation since the projector may have to be lifted up to allow the adjustable legs to be adjusted. Moreover, the process of adjusting the viewing angle of the projected image may require the legs to be adjusted several times through trial and error. To correct this problem, a simpler way of adjusting an offset of projected images is needed.
Adjustable lenses are available on the market for changing the focus of projected images. However, adjustable lenses can have the problem of emitting light at the wrong angle. Using the adjustable lenses in conjunction with an adjustable illumination optics system would improve the situation, but there are no adjustable illumination optics systems currently in use in projectors.